Strike-off bar structure



June 4, 1968 R. L. OLSON STRIKE-OFF BAR STRUCTURE Filed Oct. 21, 1965 mvENmR.

Rum/420 Z. 04 $0M United States Patent 3,386,141 STRIKE-OFF BAR STRUCTURE Richard L. Olson, Hickory Hills, Ill., assignor to Dike- O-Seal, Incorporated, Chicago, 11]., a corporation of Illinois Filed Oct. 21, 1965, Ser. No. 500,044 11 Claims. (Cl. 25-404) This invention relates to improvements in strike-off bar structures of the type which are used in the foundry industry and the like for smoothing off the sand in molding flasks and in other types of molding, of which cement finishing is one form, in which the surface of loose material, Whether dry or in a plastic or fluid state, must be leveled off to a plane with molding equipment parting faces, screeds, and the like.

Heretofore metal and wooden strike-off bars have been used but they have been extremely short lived where the material to be struck off to a plane is of an abrasive character, such as sand or a mixture containing sand. Once the edge of a strike-off bar becomes worn it is useless for the intended purpose because it will not form a plane surface in the strike-off operation. With wooden and metal bars it has been customary to plane or machine the surfaces into a true line. Under severe usage this must be repeated with such frequency that very soon repeated restraightenings of the strike-off edge or edges of the bar have it whittled down to a useless condition.

An important object of the present invention is to provide a new and improved strike-off bar construction which is light in weight and retains its shape even though used for striking off highly abrasive material.

Another object of the invention is to provide a new and improved strike-off bar having surfaces extremely resistant to abrasion.

A further object of the invention is to provide a new and improved strike-off bar having a light weight core and a highly resistant synthetic plastic body affording the strike-off edges and surfaces.

Yet another object of the invention is to provide a new and improved strike-off bar construction and attachable handle assembly.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of certain preferred embodiments thereof taken in conjunction with the accompanying drawing in Which:

FIGURE 1 is a fragmental elevational view of a strikeoff bar embodying features of the invention;

FIGURE 2 an enlarged transverse sectional view taken substantially on line 11-11 of FIGURE 1;

FIGURE 3 is a sectional view similar to FIGURE 2 but showing a modification;

FIGURE 4 is a sectional view similar to FIGURES 2 and 3 but showing still another modification; and

FIGURE 5 is a fragmental longitudinal sectional elevational view through a strike-off bar embodying the invention and showing a modified handle structure.

A strike-off bar (FIGS. 1 and 2) comprises an elongated body 11 having a plurality of sides which in this illustrated form are in equilateral triangular form with the faces defining the three sides joining along longitudinal strike-off edges 12. At least the faces and edges of the body 11 are constructed to be highly abrasion resistant. This is attained practically by molding the body 11 of an abrasion resistant synthetic plastic material, of which cast solid polyurethane, generally referred to as urethane, is a prime example. That material is as near to abrasion-proof as is presently economically available. It is relatively light in weight and has excellent form-retaining characteristics and lends itself to easy casting techniques of manufacture.

3,386,141 Patented June 4, 1968 As a material saving feature as well as a weight reducing and reinforcing feature, a central tubular core 13 is provided for the bar 10. The diameter of this core is as large as practicable consistent with adequate covering thereof by the material of the body 10 where the perimeter of the core approaches the respective sides of the body so that there will be efficient connection between the larger masses of the body material in line with the edges 12. Tubing wall thickness of the core 13 and the grade and kind of material thereof are also chosen to suit the size and length and the anticipated bending pressures to which the bar may be subjected in use. Steel or aluminum tubing, and the like, may be utilized, or solid rod or bar stock may be used.

To assist in manipulation of the bar 10, handle means are provided on its opposite ends. Conveniently, the core rod 13 has its opposite end portions projecting a suitable distance beyond each end of the bar body 11 to afford such handles 13a which may, or may not, as preferred, be provided with handle bar grips 14.

If preferred, the strike-off bar, identified as 10 in FIG- URE 3, may be provided with a quadrangular crosssectional shape, such as square or other rectangular shape, thus affording an additional strike-off edge 12 as compared with a bar of triangular cross-section.

Also, if preferred, the bar 10 as shown in FIGURE 4 may have a different triangular cross section such as of right triangular form affording a hypotenuse face which is wider than the other faces and one right angle edge 12.

On reference to FIGURE 5, the strike-01f bar 10", instead of using end extensions of the tubular core rod 13 as handles, has the ends of the core rod flush or substantially fiush with the opposite ends of the bar body 11, and a separately formed handle 15 is adapted to be applied to each opposite end of the bar. While the handle 15 may be formed from metal as a forging or casting, it is desirably made as a polyurethane casting. Extending axially from the hand-grip portion of the handle 15- is a stem 17 dimensioned to fit snugly within one of the respective sockets conveniently provided in and by the outwardly opening end portions of the bore of the tubular core rod 13. A lead-in taper 18 is desirably provided on the tip of the stem 17 to facilitate starting of the stem 17 which for tight gripping interengagernent with the core tube is preferably slightly over size in diameter compared to the core tube bore, but, especially where it is of urethane, can readily be driven into assembled position by relatively press-fitting it by pounding in on the end of the handle grip portion. Desirably a stop shoulder 19 at juncture of the smaller diameter stem 17 with the larger diameter handle grip portion of the handle 15 opposes the end of the body 11 and the core tube 13. This separate handle arrangement also makes it convenient to provide stock lengths of the strike-off bar bodies greater than may normally be desired in a strike-off bar unit by the user, when can then cut off from the stock length sections of as long or short length as desired and drive the separately supplied handles into working assembly with the size or sizes of strike-off bar sections preferred.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A strike-ofi bar of the character described comprising:

a substantially rigid elongated core;

a body molded on and about said core and comprising a highly abrasion-resistant plastic material, said body having a plurality of angularly related faces joining on strike-oif edges; and

handle means on the opposite ends of the core projecting endwise beyond the body.

2. A strike-01f bar as defined in claim 1, in which said core extends beyond the ends of the body and provides the handle means.

3. A strike-01f bar as defined in claim 1, in which said core provides a socket at each opposite end and the handle means comprise separate handles having stem portions driven into said sockets.

4. A strike-oh? bar as defined in claim 1, in which said body has at least three strike-off edges.

5. A strike-off bar as defined in claim 1, in which said body is of equilateral triangular cross section affording three strike-01f edges.

6. A strike-off bar as defined in claim 1, in which said bar is of right triangular cross section providing three strike-off edges.

7. A strike-oil bar as defined in claim 1, in which said body is of quadrangular cross section providing four strike-off edges.

8. A strike-oft bar construction of the character described comprising:

an alongated tubular light weight substantially rigid core;

a polyurethane body molded on said core in substantially uniform relation thereabout and having a plurality of substantially fiat faces respectively joining on strike-off edges; and

handle projections on said core extending beyond each opposite end of said body.

9. A strike-off bar as defined in claim 8, in which said handle projections have hand-grip coverings thereover.

10. A strike-off bar construction comprising:

and

respective handles having attachment stems secured in said sockets and having shoulders opposing the ends of the body.

11. A strike-off bar construction of the character de- 10 scribed comprising:

an elongated lightweight substantially rigid core; and

a synthetic plastic body having the shape-retaining and high abrasion resistance characteristics of polyurethane molded on said core in substantially uniform relation thereabout and to a substantial thickness and having a plurality of substantially flat faces respectively joining on strike-oil edges.

References Cited UNITED 30 WILLIAM J. STEPHENSON, Primary Examiner. 

1. A STRIKE-OFF BAR OF THE CHARACTER DESCRIBED COMPRISING: A SUBSTANTIALLY RIGID ELONGATED CORE; A BODY MOLDED ON AND ABOUT SAID CORE AND COMPRISING A HIGHLY ABRASION-RESISTANT PLASTIC MATERIAL, SAID BODY HAVING A PLURALITY OF ANGULARLY RELATED FACES JOINING ON STRIKE-OFF EDGES; AND HANDLE MEANS ON THE OPPOSITE ENDS OF THE CORE PROJECTING ENDWISE BEYOND THE BODY. 